US2824552A - Drive for blower, fan and water pump of two-stroke v-type engines - Google Patents

Description

b- 25, 1958 A. SCHEITERLEIN 2,824,552

DRIVE FOR BLOWER, FAN AND WATER PUMP OF TWO- STROKE V-TYPE ENGINES Filed Jan. 15, 1957 2 Sheets-Sheet l INVENTOR ATTORNEY 1958 A. SCHEITERLEIN 2,824,552

DRIVE FOR BLOWER, FAN AND WATER PUMP OF TWO-STROKE VTYPE ENGINES- Filed Jan. 15. 1957 Sheets-Sheet 2 r/az INVENTOR ATTORNEY DRIVE FOR BLOWER, FAN AND WATER PUMP ,OF TWO-STROKE V-TYPE ENGINES Andreas Scheiterlein, Graz, Austria, assignor to Gustav Ospelt, Vaduz, Liechtenstein Application January 15, 1957, Serial No. 634,337

Claims priority, application Austria January 20, 1956 3 Claims. (Cl. 12341.46)

The present invention relates to apparatus for driving Un w m atfifU Y a scavenging-air blower or supercharger and the fan and water pump on V-type two-stroke internal combustion engines.

In the usual design of two-stroke internal combusti'n engines of the V-type, the scavenging-air blower and the manifold for the compressed scavenging air are located in the V-space between the rows or banks of cylinders. At the same time, it is advisable, in order best to use the available V-space, to make the manifold integral with the crankcase. The drawback of this arrangement is that the conventional gear drive of the scavenging-air blower from the engine crankshaft requires, as the distance be tween the blower shaft and the crankshaft is relatively large, either large-sized gears, or if the gear diameters are to be small, a large number of gears. The complexity and weight of such gears has greatly hindered locating the scavenging-air blower and manifold in the V-space, even though such location is clearly the most convenient and efiicient. The almost exclusive use of gears for driving the scavenging-air blower of V-type engines of conventional design is owing solely to the fact that so far no other type of drive, affording the same safety and durability of operation as gears, has been available to transmit the large driving power required.

The recent developments in heavy-duty V-belt design offer the possibility of using V-belts instead of gears for driving the scavenging-air blowers of V-type engines mounted in the V-space between cylinder banks. From the above it will be clear that the main advantage of V- belts lies in the greater freedom they permit in the arrangement of the scavenging-air blower, as it is no longer necessary to keep its distance from the crankshaft as short as possible. Roots-type blowers for in-line engines are often driven with V-belts, the blower usually being flangeconnected to a sidewall of the crankcase and its drive shaft almost level with the crankshaft. This results in an approximately horizontal belt drive and permits a beltdriven water pump and fan, mounted on the shaft of the pump rotor, even though the pump and fan are placed in the middle of the free end of the engine above the crankshaft, without any interference with the belt drives of the blower from the crankshaft. However, the situation is different in a V-type engine with the blower located inside the V-space, as described in the preceding paragraph, and interference between the pump and fan drives on the one hand, and the blower drive on the other hand is bound to occur.

Still, the preferable location of the V-belt drive for the scavenging-air blower is at the free end of the crankcase, even though it is also the place for the water pump and fan drives. This is not only because other necessary drives or gears, for example, those for the injection pumps and the camshafts, must be accommodated at the flywheel end, but also because the scavenging-air blower for its best operation should preferably be located directly behind the fan, if possible, in order to take full advantage of the cooling etfect of the air current pro- 2,824,552 Patented Feb. 25, 1958 duced by the latter. In addition, placing the blower and fan drives at the same crankshaft end permits the use of a single crankshaft drive pulley for both, requiring at most only separate grooves thereon, if necessary of different diameters, for the belts of each of the two drives. This, in turn, allows shorter engine lengths. The problem therefore is to find a design for the drives of the blower, fan and water pump, when all are positioned at the free end of the engine, which will prevent interference between the strands of the blower drive on the one hand, and the driven pulley on and the bearing housing for the pump and fan shaft on the other hand. 7

According to the present invention it is proposed to operate the scavenging-air blower, the fan and the water pump by-means of belt drives located at the free end of the engine and to arrange the shaft and its bearing housing for the fan and the water pump inside the space enclosed by the drive belts of the blower, the strands of the blower belts running over idler pulleys positioned between the crankshaft and blower pulleys, but far enough to each side of the plane throrgh their axes so that the pump and fan shaft, together with the parts constituting its bearings, can be accommodated inside the blower drive belts.

The mountings of the idler pulleys can also be equipped by any one of well known means to servesimultaneously as tensioner pulleys for the blower drive. Furthermore, provided the location of these idler pulleys relative ,to the plane through the axes of the pump and fan shaft and the engine crankshaft is approximately chosen, an idler pulley equipped with similar means for applying tension to the drive belt for the fan and the water pump can be mounted on the same shaft as is used for those of the blower drive belts.

It is therefore the primary object of the present invention to provide a drive means for a scavenging-air blower or supercharger to permit the mounting thereof in the V-space of V-type engines without interference with the fan and water pump drives.

Other and further objects will be apparent from the following description of the preferred form of the invention, taken in conjunction with the drawings, in which:

Figure l is a side elevation of a V-type engine with parts in section;

Figure 2 is a front view with a part section taken on line IIII of Figure l; and

Figure 3 is a side elevation of a detail of an idler pulley as viewed from the line III-III of Figure 2.

The crankcase is designated A, :and the heads of the cylinders arranged in V-configuration, B. Driven pulley 14' is mounted on drive shaft 1 of scavenging-air blower 2, here shown as a Roots-type blower, and is driven by means of V-belts 3 from drive pulley 4 mounted on engine crankshaft 14. Another pulley 4, smaller in diameter than pulley 4 and also mounted on crankshaft 14, drives water pump drive shaft 6, by means of V- belt 5, on opposite ends of which fan 7 and pump rotor 8 are mounted. Pulley 4' may be made integral with pulley 4 if desired. Bearings 16 for shaft 6 are mounted within a cylindrical extension of pump casing 10, as shown in Figure 1, :and sleeve 9a, adapted to rotate freely about the extension of pump casing 10, has a pulley 9 thereon and one end of sleeve 9a is attached to shaft 6 near fan 7 so that pulley 9 drives shaft 6, fan 7 and pump rotor 8. To avoid interference between drive belts 3 and pulley 9, sleeve 9a and drive belt 5, idler pulleys 11 are mounted between but far enough to one side of shafts 1 and 14 so that the water pump, its drive assembly and the fan may be contained within the area defined by belts 3.

Idler pulleys 11 are mounted on arm 12 which is pivoted about stub axle 13 mounted on the engine so that idler pulleys 11 are in the position described in the preceding paragraph. A similar pulley 11 can be'mounted on arm 12', also pivoted about stub axle 13 to provide an idler pulley for belt 5. If desired, arms 12 and 12 can be loaded in any Well known manner as exemplified by the tension spring ISinterconnected between arm 12 and the engine housing in Figure 2, 'so that idler pulleys 11 and 11' and their associated arms act also -as tensioners for drive belts 3 and 5, respectively.

Having thus described my invention, What is claimed as new and desired to be secured by Letters Patent is:

tion between the blower and the free end of the crankshaft, a bearing housing on said engine adjacent the free end of saiddrive shaftsupporting the latter for rotation, said drivecomprising a first crankshaft pulley mounted on the free end of the crankshaft, a sleeve rotatably mounted about the bearing housing of the said common drive shaft and having at one end thereof a drive pulley for the water pump and cooling fan co-planar with the said first crank shaft pulley, said sleeve being attached at one end thereof to said drive shaft between the cooling fan and the free end of the engine, a first idler pulley coplanar with the last named two pulleys, a V-belt passing around the last named three coplanar pulleys, means mounting said idler pulley on the engine, a multi-V-belt drive pulley for the blower mounted on the drive shaft thereof, a second crankshaft pulley mounted on the crankshaft adjacent said first crankshaft pulley and coaxial therewith, a second idler pulley co-planar with said blower drive pulley and said second crank shaft pulley, multi- V-belts passing around said second idler pulleys, said second crank shaft pulley and said blower drive pulley, means mounting said second idler pulley on the engine, said last named three pulleys being positioned so that the planes through the V-belts around each intersect said sleeve between the cooling fan and the free end of the engine, and said idler pulleys being positioned at a sulficient distance to one side of the plane through the axes of the blower drive shaft and the crankshaft so that the shaft of the water pump, said sleeve and said pulley thereon are freely operable within the area defined by said multi-V-belts.

2. A V-belt drive as claimed in claim 1 wherein said first named mounting means comprises a stub axle mounted on the engine, a first arm pivotally mounted at one end thereof on said stub axle, said first named idler pulley being rotatably mounted on the other end of said first arm, and said second named mounting means comprises a second arm pivotally mounted at one end thereof on said stub axle, said second named idler pulley being rotatably mounted on the other end of said second arm.

3. A V-belt drive as claimed in claim 2 wherein means is operatively associated with one of said arms for resiliently urging said arm about said stub axle, whereby the pulley carried by said one arm will act as a belt tensioner.

No references cited.

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